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The type la supernova rate at z ≈ 0.5 from the supernova legacy survey

  • Author(s): Neill, JD;
  • Sullivan, M;
  • Balam, D;
  • Pritchet, CJ;
  • Howell, DA;
  • Perrett, K;
  • Astier, P;
  • Aubourg, E;
  • Basa, S;
  • Carlberg, RG;
  • Conley, A;
  • Fabbro, S;
  • Fouchez, D;
  • Guy, J;
  • Hook, I;
  • Pain, R;
  • Palanque-Delabrouille, N;
  • Regnault, N;
  • Rich, J;
  • Taillet, R;
  • Aldering, G;
  • Antilogus, P;
  • Arsenijevic, V;
  • Balland, C;
  • Baumont, S;
  • Bronder, J;
  • Ellis, RS;
  • Filiol, M;
  • Gonçalves, AC;
  • Hardin, D;
  • Kowalski, M;
  • Lidman, C;
  • Lusset, V;
  • Mouchet, M;
  • Mourao, A;
  • Perlmutter, S;
  • Ripoche, P;
  • Schlegel, D;
  • Tao, C
  • et al.

Published Web Location

https://doi.org/10.1086/505532
Abstract

We present a measurement of the distant Type la supernova (SN Ia) rate derived from the first 2 yr of the Canada-France-Hawaii Telescope Supernova Legacy Survey. We observed four 1° × 1° fields with a typical temporal frequency of (Δt) ∼ 4 observer-frame days over time spans of 158-211 days per season for each field, with breaks during the full Moon. We used 8-10 m class telescopes for spectroscopic follow-up to confirm our candidates and determine their redshifts. Our starting sample consists of 73 spectroscopically verified SNe la in the redshift range 0.2 < z < 0.6. We derive a volumetric SN Ia rate of r V(〈z〉 = 0.47) = [0.42 0.090.13(syst.) ± 0.06(stat.)] × 10 -4 yr -1 Mpc 3, assuming h = 0.7, Ω m -0.3, and a flat cosmology. Using recently published galaxy luminosity functions derived in our redshift range, we derive a SN Ia rate per unit luminosity of r L(〈z〉 = 0.47) = 0.154 -0.0330.048(syst.) 0.0310.039(stat.) SN units. Using our rate alone, we place an upper limit on the component of SN la production that tracks the cosmic star formation history of 1 SN la per 10 3 M ⊙ of stars formed. Our rate and other rates from surveys using spectroscopic sample confirmation display only a modest evolution out to z = 0.55. © 2006. The American Astronomical Society. All rights reserved.

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